the Anatomy of the Genus Selaginella, Spr. 133 
Dorsal leaf. Ovate, with long cusp; margins warty and spiny. 
Sclerotic fibres occur among the ligular epidermal cells, though no 
stomata are present on this face. These are, however, numerous on 
the aligular face. 
Section. As in the type. 
8. S. Karsteniana, A. Br. 
Ventral leaf. Leaves large, very oblique ovoid, blunt apically and 
with basal wings, very faintly spiny. The polygonal cells of the 
ligular surface are more elongated and wavy towards the margins ; 
stomata are absent. Sclerotic warty fibres occur on the aligular 
surface. The stomata are very peculiar. Frequently the walls of the 
guard-cells are so much thickened as to almost or quite obliterate the 
lumina, as I have figured in -S', concinna (Fig. 7). The surrounding 
epidermal cells are also greatly thickened. It is difficult to see how 
these stomata can serve any physiological purpose, at least in the 
mature leaf. I may say in this connexion that I invariably examined 
leaves taken from several parts of the plants studied, avoiding the very 
young leaves near the apex, and the old leaves on the basal regions of 
the stem. 
Dorsal leaf. Leaves ovate pointed and faintly spiny. Stomata 
occur both on and near the margins. The stomata on the aligular 
face were in many cases sclerotic, as in the case of the ventral leaf. 
Section. As in the type, 
9 . S. suberosa, Spr. (Fig. 19,) 
Ventral leaf. Ovate-lanceolate, bluntly pointed with spiny margins. 
The margins have warty sclerotic cells every here and there, except 
where marginal stomata occur, Warty sclerotic fibres also occur 
among the aligular epidermal cells, the stomata being confined to the 
region over the midrib. 
Dorsal leaf. Ovate with backwardly directed wings, spiny sclerotic 
margin, and a long cusp. No stomata occur on the ligular face. The 
sclerotic fibres on the aligular face are very long, thick-walled, highly 
refractive, and warty. Stomata occur over the midrib, and a very few 
at the margins of the basal lobes. 
Section. As in the type. 
Fig. 19 shows a section of the ventral leaf. The ligular epidermis 
consists of peg-shaped cells with every here and there sclerotic fibres. 
